Codebook Performance Evaluation of mmWave in Train Communications.

Improved coverage, high data rates and Quality of Service (QoS) constitute important features of 5G networks. The spectrum limitations, currently faced in 4G, will be resolved by adapting millimeter-Wave (mmWave) frequencies technologies, which will also result in high throughput. High mobility scenarios will pose additional challenges, in 5G communications, due to the rapid change in the environment, i.e. channel coefficients and Doppler effect. In this paper, we introduce our research on the achievable throughput, coverage and Signal-to-Noise-Ratio (SNR), considering a High-Speed Train (HST) traveling on two different rail scenarios in the UK. Applying two beamforming (BF) techniques (maximum ray selection and codebook based) and employing a fixed beam pattern in the antennas, we compare the performance of the different schemes, considering different distances between the Access Points (APs) at the rail track, looking also at the minimum network requirements to maintain connection. We show that overall the employment of BF improves the achievable throughput and SNR, with the codebook based approach achieving constant coverage with stable throughput in a 300m radius mmWave cell.